Brian Norris <briannorris@xxxxxxxxxxxx> writes:
> On Tue, Dec 8, 2020 at 7:14 AM Xiaohui Zhang <ruc_zhangxiaohui@xxxxxxx> wrote:
>>
>> From: Zhang Xiaohui <ruc_zhangxiaohui@xxxxxxx>
>>
>> mwifiex_config_scan() calls memcpy() without checking
>> the destination size may trigger a buffer overflower,
>> which a local user could use to cause denial of service
>> or the execution of arbitrary code.
>> Fix it by putting the length check before calling memcpy().
>
> ^^ That's not really what you're doing any more, for the record. But
> then, describing "what" is not really the point of a commit message
> (that's what the code is for), so maybe that's not that important.
>
>> Signed-off-by: Zhang Xiaohui <ruc_zhangxiaohui@xxxxxxx>
>> ---
>> drivers/net/wireless/marvell/mwifiex/scan.c | 2 +-
>> 1 file changed, 1 insertion(+), 1 deletion(-)
>>
>> diff --git a/drivers/net/wireless/marvell/mwifiex/scan.c b/drivers/net/wireless/marvell/mwifiex/scan.c
>> index c2a685f63..34293fd80 100644
>> --- a/drivers/net/wireless/marvell/mwifiex/scan.c
>> +++ b/drivers/net/wireless/marvell/mwifiex/scan.c
>> @@ -931,7 +931,7 @@ mwifiex_config_scan(struct mwifiex_private *priv,
>> wildcard_ssid_tlv->max_ssid_length = 0xfe;
>>
>> memcpy(wildcard_ssid_tlv->ssid,
>> - user_scan_in->ssid_list[i].ssid, ssid_len);
>> + user_scan_in->ssid_list[i].ssid, min_t(u32, ssid_len, 1));
>
> This *looks* like it should be wrong, because SSIDs are clearly longer
> than 1 byte in many cases, but you *are* right that this is what the
> struct is defined as:
>
> struct mwifiex_ie_types_wildcard_ssid_params {
> ...
> u8 ssid[1];
> };
>
> This feels like something that could use some confirmation from
> NXP/ex-Marvell folks if possible, but if not that, at least some
> creative testing. Did you actually test this patch, to make sure
> non-wildcard scans still work?
>
> Also, even if this is correct, it seems like it would be more correct
> to use 'sizeof(wildcard_ssid_tlv->ssid)' instead of a magic number 1.
Xiaohui, please respond to Brian's comments. If you ignore review
comments I have a hard time trusting your patches.
Also when you submit a new version you should mark it as v2. See more in
the wiki link below.
--
https://patchwork.kernel.org/project/linux-wireless/list/
https://wireless.wiki.kernel.org/en/developers/documentation/submittingpatches
